WO2008125679A1

WO2008125679A1 - Method and apparatus for chromatographic component separation with partial recirculation of mixture fractions

Info

Publication number: WO2008125679A1
Application number: PCT/EP2008/054571
Authority: WO
Inventors: Lars Christian Kessler; Andreas Seidel-Morgenstern
Original assignee: MAX-PLANCK-Gesellschaft zur Förderung der Wissenschaften e.V.
Priority date: 2007-04-17
Filing date: 2008-04-16
Publication date: 2008-10-23
Also published as: EP1982752B1; US8282831B2; EP1982752A1; US20100186587A1; DE502007004854D1; ATE478718T1

Abstract

The invention describes a method for the chromatographic component separation of a multicomponent fluid mixture by means of the simulated moving bed method, wherein the multicomponent fluid mixture (41) and at least one solvent (42) are fed into a plurality of chambers (49-52) or chamber sections containing at least one solid substance at a first and second inlet (45, 46); and an extract flow (44), which contains at least one first component (79) separated from the multicomponent fluid mixture (41), and a raffinate stream (43), which contains at least one second component (72) separated from the component fluid mixture (41), are conducted away from the chambers (49-52) or chamber sections at a first and second outlet (47, 48), wherein said chambers (49-52) or chamber sections are connected to each other in series, forming a closed circuit (57), and junction points are each newly positioned between first and second inlets and outlets (45-48) which are arranged between two chambers (49, 50; 50, 51; 51, 52; 52, 53) or chamber sections of the circuit (57) after the running of a cyclic timing unit between two additional chambers or chamber sections of the circuit, wherein the raffinate stream (43) and/or extract flow (44) conducted away at the first and/or second outlet (47, 48) are/is at least partly temporarily stored in at least one tank (62) mounted therebetween and are/is fed (66) in one timing unit to the first and/or second inlet (45, 46) alternatingly or simultaneously with the multicomponent fluid mixture (64) and/or the solvent in reverse coupling to the chambers or chamber sections.

Description

Method and apparatus for the chromatographic separation of components with partial recycling of mixture fractions

description

The invention relates to a method for the chromatographic separation of components of a multicomponent fluid mixture by means of the simulated moving bed method according to the preamble of patent claim 1. An apparatus for carrying out the method is described.

Such state-of-the-art processes are used, in particular in the pharmaceutical and chemical industries, to separate components of a high-purity substance mixture even if the mixture is a complex multicomponent fluid mixture whose components may additionally have a Have temperature sensitivity. In this case, the different affinity of the components to be separated with respect to a solid (preferably adsorbent material) is utilized for their separation.

Conventionally, chromatographic separations are carried out discontinuously in the so-called batch process. In such a batch process, a solid-filled chamber (separation column) is flowed through by a solvent (eluent). A limited amount of the sample to be separated is injected into a solvent stream. Due to the differences in the strength of the interactions, the components migrate at different speeds through the separation column and leave it at different times. points. This injection can be repeated only after a certain period of time, without affecting the separation success of the previous injection.

For a continuous mode of operation, a countercurrent flow is created between the solvent-containing liquid and the solid phase. For this, the solid phase is moved in the opposite direction to the liquid phase.

In such an operation in countercurrent process, the Mehrkomponentenflu- idmischung can be applied continuously in the middle of the separation column. With suitably selected liquid to solid phase flow ratios, the more strongly interacting component moving with the solid may be directed in the direction of an extract stream withdrawn from the separation column and the weakly interacting component moving with the liquid phase toward a likewise derived raffinate stream.

The separation methods can be operated in a continuous mode of operation according to the known simulated moving bed (SMB) method. Such methods are applied to devices which are generally composed of at least four circulating separation zones, which consist of at least one chamber or a chamber section. The actual countercurrent of the solid phase is simulated by periodically moving the solid statically arranged in individual chambers in the opposite direction to the flow of the solvent. This corresponds to the moving column principle. Alternatively, with fixed chambers, the positions of the inlets and outlets can also be cyclically offset. This corresponds to the moving port principle. The time between two switching operations is called the cycle time. The zones are divided by two inputs, each for the

Multi-component fluid mixture and the solvent, and limited by two outputs, each for the extract and the raffinate. The separation of the components takes place as far as possible in two of the four zones, whereas the two other zones serve for the regeneration of the solid and liquid phases.

Such a SMB method results in a repetitive regime after a certain time. This is called a cyclic-stationary state. In this state, there are characteristic, repetitive after a cycle time concentration profiles in the outlet streams caused by the periodic switching. US Pat. No. 2,985,589 describes such an SMB process for the continuous chromatographic separation of multicomponent fluid mixtures with a fixed adsorbent bed containing solids and repositionable inlets and outlets.

The method described in US Pat. No. 2,985,589 is operated with constant operating parameters, such as the volume flows supplied and withdrawn, the duration of a clock unit and the concentrations of the multicomponent fluid mixture supplied and the solvent. It will be referred to hereinafter as the "conventional method".

US Pat. No. 5,102,553 describes an SMB process in which the added and removed volume flows of the multicomponent fluid mixture, the solvent, the extract stream, the raffinate stream and the circulating circulation streams are designed to be variable in time within one cycle unit ("power feed" method) An increase in productivity over SMB processes with constant operating parameters can be achieved.

WO A 0025885 proposes a process which provides asynchronous switching of feeds and outlets. This corresponds to the VariCol process. In contrast to the conventional SMB methods, the connection points of the inlets and outlets are repositioned at different times, resulting in variable separation zone lengths per time unit. In this way, an increase in productivity is achieved.

In US 2006/023459 a variation of the VariCol method is shown in which between two zones the concentration of the stream is increased by an additional process step.

WO 2004014511 describes an SMB process in which the concentration of the incoming multicomponent fluid mixture is changed within one cycle unit. This corresponds to the ModiCon method.

In this process, by feeding a more concentrated multicomponent fluid mixture, for example, in the fourth quarter of a cycle time, an increase in productivity, the product concentration and a reduction of the specific solvent consumption can be achieved.

US 2 985 589, US 5 102 553 and WO 200401451 1 describe processes based on continuous collection of the exiting extract and raffinate streams. These methods must be operated in such a way that averaged over the entire cycle time a predetermined high integral purity can be achieved. This leads to loss of productivity at very high target purities.

Alternatively, in Y.S. Bae and C-H. Lee "Partial-discard strategy for obtaining high purity products using simulated mobile bed chromatography", Journal of Chromatography A, 1 122: 161-173 (2006) proposed an SM B method in which within a cycle time only part of the exiting extract The unrecorded portion is discarded in the method described, and recirculation of the unaccumulated portion into the reservoir tank of the initial multicomponent fluid mixture is proposed only in the case where this tank is large and large the proportion to be recycled may be small in order not to change the inlet concentration of the multicomponent mixture The method described in Journal of Chromatography A, 1 122: 161-173 (2006) has the disadvantage that partial discarding of the outlet stream leads to losses in productivity and yield ,

Accordingly, it is an object of the present invention to provide a method for the chromatographic separation of components of a multi-component fluid mixture by means of the simulated moving bed method, which has a high productivity with a high predetermined degree of purity of the separated components as well as a reduction of the Operating costs enabled. It should also be provided an apparatus for performing the method.

This object is achieved on the method side by the features of claim 1 and on the device side by the features of claim 18.

An essential point of the invention is that according to the invention, in a method for the chromatographic separation of components of a multicomponent fluid mixture by means of a simulated moving bed method, the first and / or second output proceed derived raffinate stream and / or extract stream at least partially stored in each case in at least one container and fed in a clock unit the first and / or second input alternately or simultaneously with the Mehrkomponentenfluidmischung and / or the solvent the chambers or chamber sections rückkoppelnd / is. For this purpose, the multicomponent fluid mixture and at least one solvent are supplied to a plurality of chambers or chamber sections containing at least one substance at the first and second inlet and the extract stream containing at least a first component separated from the multicomponent fluid mixture and the raffinate stream containing at least a second of the Component component containing multicomponent fluid mixture, derived from the chambers or chamber sections at a first and second output. The chambers or chamber sections form a closed circuit and are thus connected in rows. The connection points of the respectively arranged between two chambers or chamber sections of the circuit first and second inputs and outputs are repositioned after the expiration of a cyclic clock unit between two other chambers or chamber sections of the circuit.

With such a method, at least one of the two exiting streams is collected to a part within a cycle unit, resulting in at least two partial streams result per outlet, of which at least one collected in at least one tank and its contents in a defined period of time within the cycle time is introduced in a freely selectable feed regime alternately or simultaneously with the initial multi-component fluid mixture in the separator. Thus, the recycled stream is not mixed with the original multicomponent fluid mixture. Rather, the differences in the concentrations of the components and the ratio of these to each other according to the invention deliberately exploited in order to achieve an increase in the purity. Compared to the ModiCon process, if the initial multicomponent fluid mixture is not introduced into the system, an already separated fraction is introduced. In this, the ratio of the components is shifted in favor of at least one component. The ModiCon method is based on utilizing nonlinearities of the adsorption isotherm, which is not limited to the subject of the present invention. It is thus the branched stream in one or more containers, for example in the form of tanks, collected and then introduced within a cyclically repeated defined period within the cycle time in a defined feed regime preferably alternately with the actual supplied multicomponent fluid mixtures in the device. The non-recirculated partial flow, which reaches the specified degree of purity, is removed from the system and collected in a storage medium provided for this purpose. This procedure can increase the productivity of the process for given purities.

According to the invention, therefore, the multicomponent fluid mixture, the content of at least one of the containers (recycled tank), which is provided for the storage of the zurückzuführenden portion of the raffinate and / or extract stream and thus contains at least one of the components and at least one solvent of a plurality of at least one solid , Preferably, adsorbent material containing chambers or chamber sections supplied at a first or second input. In this case, within the cycle time at a defined time, the feed of either a container containing exclusively the multicomponent fluid mixture is switched over to at least one recycling tank or of at least one recycling tank to the container of the multicomponent fluid mixture. This is done by means of a valve. The timing and sequence of such switching have an influence on the separation performance of the device implementing the method according to the invention.

Within the cycle time, at least one of the components or outlet streams derived from the device is diverted into at least one of the recycling tanks.

After expiration of a cyclically repeating cycle time, the chambers are displaced by a multi-position valve by one position in the opposite direction to the flow of the fluid mass. Alternatively, the connection points of the respectively arranged between two chambers and chamber sections of the circuit first and second inputs and outputs are repositioned after a cyclic cycle time between two other chambers or chamber sections of the circuit. It is also possible to operate in an open-loop SMB, in which case the regeneration zone of the liquid phase can be omitted, reducing the number of zones to three.

Advantageously, the subject of the present invention can be applied to conventional SMB

Procedures and devices that use them. A combination of the method according to the invention with methods which vary the volume flow of the incoming multicomponent fluid mixture within one cycle time ("power feed") is also possible In the case of the presence of non-linear adsorption isotherms, a combination with the ModiCon method is also possible the method according to the invention can be used for processes with asynchronous switching times ("VARICOL").

The feedback feed of the derived raffinate stream and / or the extracted extract stream can be carried out within a clock unit following the discharge or take place within the same cycle unit.

According to a preferred embodiment, in at least a first time segment of the clock unit, the entire discharged raffinate stream and / or extract stream is removed as a product of the desired degree of purity, and the entire discharged raffinate stream and / or extract stream are fed back in an at least second period of the cycle unit.

Both the pressure and the temperature of the supplied multicomponent fluid mixture and / or of the solvent can be changed step by step and / or continuously within one cycle unit.

The composition of the solvent and the content of at least one additional co-incorporated modifier in the multicomponent fluid mixture may preferably be changed stepwise and / or continuously.

It is used according to a preferred embodiment, at least one solid which is suitable for causing different migration speeds of the individual components of the multi-component fluid mixture in the individual chambers or chamber sections. This may be an adsorbent material. According to a preferred embodiment, the solvent used is a mixture of a plurality of fluids and / or a mixture of at least one fluid with a low or high molecular weight modifier.

As the solvent and / or multi-component fluid mixture, a gas or a mixture of a plurality of gases which are in the supercritical or subcritical state may be used.

The solvent may also contain components to be separated. Here, the solvent with the components to be separated and the solvent without the components to be separated have different compositions and / or abilities with regard to influencing a bonding behavior of the components to be separated from the solid.

In the chambers or chamber sections, a chemical reaction for the preparation and separation of the components can be carried out.

The junctions of the first and second inputs and outputs are repositioned at different times.

At least one volume flow of the multicomponent fluid mixture of the solvent, the extract stream, the raffinate stream and in-circuit circulating streams within one cycle unit are changed stepwise and / or continuously.

A device for carrying out such a method is shown, which advantageously consists of at least four chambers with intermediate inputs and outputs. For branching off that portion of the derived raffinate or extract stream, a first valve, which switches between the stream to be discharged from the device and the stream to be recycled, and a second valve, which switches between the multicomponent fluid mixture to be fed and the stream to be recycled into the device, are additionally arranged , Between the first and second valve at least one container for temporary storage or intermediate storage of the branched stream is arranged. Further advantageous embodiments will become apparent from the dependent claims.

Advantages and expediencies can be found in the following description in conjunction with the drawing. Hereby show:

Figure 1 is a schematic representation of an apparatus for performing a method for the chromatographic separation of components according to the known from the prior art SMB method according to the Moving Column principle.

2 is a schematic representation of an apparatus for carrying out a method for the chromatographic separation of components according to the SMB method known from the prior art according to the moving-port principle;

Fig. 3 is a graph showing exemplary concentration profiles on a raffinate outlet of a device using the conventional SMB method;

Fig. 4 is a diagram showing exemplary concentration profiles at an extract outlet of an apparatus using the conventional SMB method;

5 is a diagram showing the course of an integral and differential degree of purity of the target component in the raffinate stream within a cycle time or clock unit in a conventional SMB method;

6 shows a schematic representation of a device for carrying out the method according to the invention according to an embodiment of the invention; FIG. 7 shows a diagram of exemplary concentration profiles of the raffinate stream of a device using the SMB method according to the invention; FIG. and

8 shows a diagram of concentration profiles of the extract stream of an apparatus using the SMB method according to the invention by way of example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic representation of an apparatus for carrying out a method for chromatographic separation according to the SMB method according to the prior art. A multicomponent fluid mixture (feed) 1 is supplied as well as a solvent (eluent) 2 at inputs 5 and 6, respectively.

A raffinate stream 3 and an extract stream 4 are withdrawn at outputs 7 and 8, respectively, of the apparatus. The device consists of a total of four chambers 9, 10, 11 and 12 acting as separation zones, which are connected in a row to one another in a circuit. Between the chambers 9, 10, 11 and 12, the connection points for the inputs 5, 6 and the connection points for the outputs 7, 8 are present.

A solid is fixed in at least one of the four chambers 9 - 12 before, wherein the chambers are flowed through the solvent at different speeds. In order to generate the countercurrent of the solid phase, the chambers are moved periodically after the lapse of one cycle time or within one cycle unit in the opposite direction to the flow of the liquid phase. The multicomponent fluid mixture to be separated is in this case continuously fed to the center of the device.

The positions of the inputs and outputs define four zones in which a different relative velocity of the liquid and solid phases is present due to a different volume flow of the liquid phase. With appropriate adjustment of these relative velocities, more strongly adsorbing components will move with the solid phase in the direction of a derived extract stream and less adsorbent components with the solvent in the direction of a derivative raffinate stream. The separation of the components largely takes place in the zones II and III, whereas the zones I and IV serve for the regeneration of the solid, which can be for example an adsorbent material, and the solvent.

The arrow 17 shows the direction of the column switching, ie the moving column principle.

The reproduced in Fig. 2 device corresponds to the reproduced in Fig. 1 device with the exception that by means of the arrow 18, the direction of the port switching, so the moving port principle is shown.

FIG. 3 is a graph showing the concentration profile at the raffinate outlet in a device using the conventional SMB method. The ordinate 19 represents the concentration of the raffinate stream, that is to say a target component A in accordance with reference numeral 21, and the proportionate soiling component B with the reference numeral 22. About the abscissa 20, the time course of the concentration is plotted.

The time course corresponds to two complete clock units or two complete cycle times. The components to be separated may be present in the multicomponent fluid mixture in a high concentration or undissolved and diluted or dissolved to a particular concentration prior to application of the SMB process. For example, both components are present in the same concentration. The conditions used in this case are summarized in a following Table 1 and the performance parameters used here in a following Table 2.

4, the extract outlet is shown in its profile, that is to say the temporal concentration profile 25 of the target component B and the temporal concentration profile 26 of the proportionate soiling component A in a diagram in which the concentration 23 is likewise plotted over the course of time 24.

Due to the switching operations, a cyclically stationary state is achieved in the SMB method. In this state, cyclically constantly repeating concentration profiles can be recognized at both outlets. Typically, a successful operation can Occurrence of the undesirable component towards the end, as the component B in the raffinate or only at the beginning, as the component A in the extract stream, a cycle time are seen.

The exiting streams are collected over the entire period. In integral terms, a purity of, for example, 88% by weight at both outlets is to be achieved over the duration of the entire cycle and thus over the entire process duration.

A cycle time can now be divided into arbitrarily short subsections. At each of these times, the differential purity and the integral purity obtained at that time at the two outlets can be determined. The differential purity indicates the ratio of the concentration of the target component and at least one non-target component leaving the considered outlet at the current time. The integral purity may indicate the ratio of the target component and at least one non-target component exiting the considered outlet from the beginning of the clock to the current time.

FIG. 5 is a diagram showing the degree of purity in% according to the ordinate 27 and the cycle time in% according to the abscissa 28 of the integral purity 29 and the differential purity 30 for the raffinate stream. It can be clearly seen that the integral purity falls below the threshold of the desired target purity at 83.0% of the cycle time (31).

FIG. 6 shows a schematic illustration of an apparatus for carrying out the method according to the invention in accordance with an embodiment of the invention. Again, a multicomponent fluid mixture 41 is supplied at an inlet 45 and a solvent 42 at an inlet 46 of the apparatus. Likewise, a raffinate stream 43 is discharged at an outlet 47 and an extract stream 44 at an outlet 48.

The device in turn consists of a total of four chambers 49, 50, 51 and 52, which are connected in a row in a closed circuit. Reference numeral 57 represents the direction of the column switching. By means of the arrows 53, 54, 55 and 56, the flow course within the chambers and the cycle formed thereby is shown.

The effluent 58 from the raffinate stream 43 at the exit 47, according to this embodiment of the invention, is transferred to an outlet valve 59 by switching depending on whether a raffinate stream having the required purity of the separated component or purity is present. In the presence of the desired purity, a switchover takes place for discharging the separated component according to the reference numeral 60. In the absence of the required purity, a switchover takes place in the direction 61, so that this separated portion of the raffinate stream into a tank or container 62, in which now typically a liquid which is enriched with a component A, is located. When the cycle time is reached, the system switches back to state 60.

A further valve 63 designed as an inlet valve is switched depending on whether the separated raffinate stream stored in the tank 62 is to be returned to the chambers via the inlet 45 or via a feed line 65 the initial multicomponent fluid mixture 41 from a storage tank 64 should be forwarded. This is done via a supply line 66.

With such a device, a combination of catching a raffinate stream only for a period of the cycle time and reintroducing the intercepted and cached portion at a later time within a cycle time may be advantageously employed in place of the original multicomponent fluid mixture. Are z. For example, as shown in FIG. 5 17% of the clock unit that does not meet the purity requirements on such a feedback of the raffinate fed back to the chambers, so an improved separation can be achieved. This is shown in Tables 1 and 2 below. Table 1

¹ to US 2,985,589

² according to Journal of Chromatography A 1122 (2006) 161 Table 1 shows selected simulation parameters for the objective function, the product of raffinate purity and productivity multiplied by extract purity and productivity.

The dimensionless cutting and inflow points result from the discretization of a cycle time in 23 (fractionation method) or 22 (method according to the invention) points. The volume difference indicates that for the selected conditions 0.0357 ml per switching time would be pumped out of the tank more so that it can be supplied by feedback. This difference is compensated by a suitable stream of pure solvent.

Table 2

¹ to US 2,985,589

² according to Journal of Chromatography A 1122 (2006) 161

Table 2 compares important performance parameters. The percentage change is calculated as follows: Change [%] = 100 value _E rfιndung - 100

VVβrt Conventional / Fractionation It should be noted that a smaller value is better for eluent consumption and loss. In the following, the definitions are briefly mentioned.

Product mass flow of raffinate for the fractionation process and the process according to the invention:

For the classic SM B process:

In all cases, the product mass flow in the extract is calculated as follows:

X l _s

Q _E * \ _Cι {t) dt

(xl) * T _s m ^Ex =

ts

The raffinate purity is:

Pur * "= m _{* 1} £ ± -

The extract purity is:

Pure ^Ex = 100

Productivity for component A:

Productivity for component B:

mξ ^x

PR _B =

Number of columns * (1 - ε) * column volume For solvent consumption (EC):

_{EC =} QmuenΛ QF _{bΣw EC =} QmuenΛ Q _F m " ¹ A m '' ¹ B

For the yield of the fractionation process and the process according to the invention, the following applies:

Yιeld _Λ = - ^Ä

^ F ^C A ¹ inlet ' ¹ S

Yield _B = - ^ £

\ CF ^C B ¹ inlet ' ¹ S

The yield for the conventional SMB process is as follows:

Yield _A = ^ ", Yield _B = ^m * _F

^Ä O zip * _C ^ A ^F O MF * c ^ B

For the loss for the conventional and the inventive method applies:

loss

^A QF ^• * r ^C A ^F * ¹ TZuIaUf 'I ¹ TS

Loss K

^A QF ^• * r ^C B ^F * ^λ T Inlet 'I ^λ TS

For the fractionation process:

Vorha

In the case of an exemplarily selected target purity of at least 88%, a broad parameter field was used in simulation studies and an operating point selected from this which has the highest value for the objective function, the quotient of the product of purity and productivity of raffinate and extract. The resulting parameters are summarized in Table 1 and the performance parameters in Table 2.

To simulate the system, the literature-known equilibrium dispersion model (G. Golshan-Shirazi and AM Katti, Fundamentals of Preparative to the Nonlinear Chroma- tography, Academic Press, Boston, MA (1994) was used.) The numerical calculation is carried out with the aid of the Rouchon Algorithm (P. Rouchon, M. Schonauer, P. Valentin and

G. Guiochon, Sei. Be. Technol. 22 (1987, p.1793). The concentrations in the solid and liquid phases are linked via the adsorption isotherm. In the considered case, this is a linear isotherm.

In Table 1 of Fig. 2, the process parameters and performance parameters for three different methods used, namely one according to US Patent US 2,985,589 as a conventional SM B method, a fractionation method (Y.-S. Bae and CH Lee, " Partial-discard strategy for obtaining high purity products using simulated movid bed chromatography ") and a method according to the invention. Each of these methods was selected to provide maximum values for the product of raffinate purity and productivity of recovery of component A, as well as the product of extract purity and productivity of recovery of component B, for a given minimum purity of 88%. The adsorption behavior of both components can be described by linear isotherms.

The method according to the invention can be implemented in various ways. The product collection period within the clock unit or cycle time is limited in the case of raffinate feedback by the start of a clock unit and the time when the integral purity falls below the required threshold. This results in a difference period between the end of the product collection period and the beginning of the next cycle unit. The flow exiting within this period no longer meets the purity requirements and is collected in at least one tank, the contents of which are also supplied to the inlet 45 at periodic intervals. In the case of an extra feedback, the integral purity increases with increasing cycle time and the contamination occurs at the beginning of a cycle time. The integral purity is determined starting from the end of the clock unit backwards towards the beginning of the bar. Thus, the product collection period is limited by the start of the collection and the end of the clock unit.

In both raffinate and extract feedback, as well as a combination of both, the performance of this method and the apparatus employing this method is affected by the duration and timing of the feedback.

For example, the outgoing current is collected only until a time before the threshold is exceeded. This corresponds to Figures 3 and 4 83%. This part is collected in a product tank following line 60. For the remaining 17% of the cycle unit, the raffinate stream in the tank 62 is collected. From this, it is then alternately, so alternately with the initial Mehrkomponentenflu- idmischung, the input 45 fed. This feedback of a raffinate stream, whose concentration ratio is typically already shifted in favor of one of the components, then again leads to an increase in the purity in the feedback raffinate stream 43 which is affected by the feedback.

The duration of the feedback is largely determined by the selection of the product collection period. The feedback period is typically between the beginning of the clock unit and the end of the clock unit. In the case of raffinate feedback, it is advantageous to realize the reflux from the tank 62 at the beginning of the cycle unit. In the case of the extra feedback, this should be exactly the opposite, ie at the end of the clock unit.

Once the time is reached at which the target purity is exceeded, the outlet valve 59 is switched so that the raffinate stream is diverted into the tank 62 for the rest of the cycle. The inflow valve then regulates when the inflow into the chambers via the inlet 45 from the tank 62 or instead the inflow of the initial multicomponent fluid mixture from the container 64 should take place. The extract stream is continuously collected and removed according to this embodiment. In FIGS. 7 and 8, the concentration profiles of the raffinate stream and the extract stream are plotted on the ordinates 67 and 74 and the abscissas 68 and 75, respectively, in their time profile. The concentration profiles are reproduced for the target component A by the reference numeral 72, for the target component B in the extract stream by the reference numeral 79, for the proportionate soiling component B by the reference numeral 73 and for the proportionate soiling component A by the reference numeral 80.

An operating point was selected from a data field determined by simulation for an exemplary selected minimum purity of 88%. The conditions considered are in turn summarized in Table 1 and the determined performance parameters in Table 2.

From the tables it can be seen that the average outlet concentration of component A in the raffinate stream has increased by 45% compared to the conventional process and by 14% compared to the fractionation process without feedback. The average outlet concentration of component B in the extract stream can be increased by 208% as compared to the conventional method. Compared to the fractionation method, it increases by 7%.

The recoverable mass flow of component A from the raffinate stream can be increased by 96% compared to the conventional process and by 9% compared to the fractionation process. The recoverable mass flow of the component B from the extract stream can be increased by 90% compared to the conventional method, compared with the fractionation method it decreases by 31%. However, this occurs at the expense of a significantly poorer yield and a high loss of components.

The productivity of component A from the raffinate stream can be increased by 95% as compared to the conventional process and by 9% as compared to the fractionation process. The productivity for the component B from the extract stream can be increased by 90% as compared with the conventional method.

The specific solvent consumption for component A from the raffinate stream is 56% compared to the conventional process and compared to fractionation. reduced by 32%. The specific solvent consumption for component B from the extract stream is reduced by 55% compared to the conventional method, compared to the fractionation method.

The yield for component A from the raffinate stream can be increased by 3% compared to the conventional process and by 78% over the fractionation process. The yield for component B from the extract stream remains at the same level as in the conventional process and increases by 29% over the fractionation process.

The loss of the component A is 9% below the level of the conventional process, compared to the fractionation process, this can be reduced by 77%. Although the loss of component B increases by 4% compared with the conventional method, it is reduced by 51% over the fractionation method.

According to Sections 70 and 71, the product collection period, that is, the period of time in which the product of the desired purity is removed from the entire apparatus, and the recycle period, that is, the period in which the raffinate stream is separated for feedback, are represented. In section 69, a previous cycle is partially reproduced. In addition, a subsequent cycle is partially reproduced.

In sections 76, 77 of FIG. 8, almost 2 cycles of the extract stream are shown.

The improvement in performance over the conventional method is achieved in that the targeted final purity of the streams must no longer be integral over the entire cycle time but only up to an earlier point in time. For this reason, higher feed streams and lower regeneration streams are possible. This allows an increase in productivity. By reducing the eluent consumption and the ability to achieve a high separation efficiency even with less efficient and thus cheaper solids, a reduction in operating costs can be achieved.

The literature-described fractionation method also has the advantage that the desired target purity does not have to be integral over the entire switching time. Indeed The process according to the invention advantageously differs from the fractionation process in the following points.

Since the volume fraction not collected as a product is not discarded but reintroduced, the yield can be increased and the loss of components can be significantly reduced. The feedback itself has a positive effect on the achievable purities, and thus also on the productivity. If, as in the example case shown in Tab. 2, the strength of the interaction of the components with the solid phase is independent of the concentration and other components involved, there are linear adsorption isotherms. In the case of raffinate feedback it is advantageous to apply the pre-separated mixture before the initial multi-component fluid mixture. In this way, at the beginning of the cycle, a smaller amount of the components not desired in this outlet is applied. By renewed passage of the separating solid phase, the purity is further increased. Since the mixture introduced at the beginning of the cycle also first reaches the exit, and in the considered case of raffinate feedback, the fraction to be collected is also at the beginning, under the same conditions, the operating points of the separation and the collection period in the product tank can be achieved Purity over the fractionation process can be increased.

This applies vice versa for the case of the extra feedback. Here, a later application of the contents of the recycling tank is advantageous.

If the strength of the interaction of the components with the solid phase depends on the own concentration and the other components involved, ie if non-linear adsorption isotherms are present, the improvement of the purities is conditioned by competitive interactions.

Of course, instead of a container which serves as a buffer, any type of other buffers may be used, such as chromatography columns.

The feedback stream can also be initiated directly without caching.

The inventive method can be applied to all imaginable and previously known SMB structures, for example, less than or more than 4 chambers exhibit. For example, such a structure may consist of 1 - 3 or 5 and more chambers.

All disclosed in the application documents features are claimed as essential to the invention, provided they are new individually or in combination over the prior art.

LIST OF REFERENCE NUMBERS

1 multi-component fluid mixture (feed)

2 solvents

3 raffinate stream

4 extract stream

5, 6 inputs

7, 8 outputs

9, 10, 11, 12 chambers

17 arrow

18 arrow

19 concentration (ordinate)

20 time course (abscissa)

21 temporal concentration course of the target component A

22 temporal concentration course of the proportionate pollution Komponen te B

23 concentration (ordinate)

24 time course (abscissa)

25 temporal concentration course of the target component B

26 temporal concentration course of the proportionate pollution components A te

27 purity in% by weight (ordinate)

28 time course (abscissa)

29 temporal course of the integral purity

30 temporal course of differential purity

31 arrow

41 multi-component fluid mixture

43 raffinate stream 44 extract stream

45 entrance

47 output

48 output 49, 50, 51, 52 chambers

53, 54, 55, 56 arrows

58 derivative

59 exhaust valve

60 switchover / line 61 direction

62 containers / tank

63 valve

64 storage tank / container

65 Supply line 66 Supply line

67, 74 concentration (ordinate)

68, 75 Time course (abscissa)

69, 70, 71 sections

72 Concentration profiles Target component A at the raffinate stream 73 Concentration profiles Proportionate soil component B

76, 77 sections

79 Concentration profile Target component B in the extract stream

80 Concentration profile Proportional soiling component A I, II, III, IV Zones

Claims

Method and apparatus for the chromatographic separation of components with partial recycling of mixture fractions Patent claims

A method of chromatographic separation of components (72, 79) of a multicomponent fluid mixture by the simulated moving bed method, wherein the multicomponent fluid mixture (41) and at least one solvent (42) of a plurality of at least one solid containing chambers (49 - 52) or chamber portions at first and second ports (45, 46), and an extract stream (44) containing at least a first component (79) separated from the multicomponent fluid mixture (41), and a raffinate stream (43) containing at least one of second separated from the component fluid mixture (41)

Component (72) are derived from the chambers (49 - 52) or chamber sections at a first and second output (47, 48) are derived, wherein the chambers (49 - 52) or chamber sections a closed circuit (57) forming in rows with each other and connecting points of each between two chambers (49, 50, 50, 51, 51, 52, 52, 53) or chamber sections of the

Circuit (57) arranged first and second inputs and outputs (45 - 48) are repositioned after expiry of a cyclic clock unit between two further chambers or chamber sections of the circuit, characterized in that at the first and / or second output (47, 48 ) derived raffinate stream (43) and / or extract stream (44) at least partially in each case in at least one buffer store, in particular a container (62), interposed and in a clock unit the first and / or second input (45, 46) alternately or simultaneously with the A multicomponent fluid mixture (64) and / or the solvent to the chambers or chamber sections fed back (66) is / will.

2. The method according to claim 1, characterized in that the feedback feed (66) of the derived raffinate stream (43) and / or extract stream (44) within one of the successful discharge (58) subsequent clock unit is performed.

3. The method according to claim 1, characterized in that the feedback feed (66) of the derived raffinate stream (43) and / or the extract stream (44) within the same clock unit in which the discharge line (58) is carried out.

4. The method according to any one of the preceding claims, characterized in that in at least a first period of the clock unit, the entire derived

Raffinate stream (43) and / or extract stream (44) is discharged as product with desired degree of purity (60) and in at least a second period of the clock unit, the total derived raffinate stream and / or extract stream (43, 44) fed back (66).

5. The method according to any one of the preceding claims, characterized in that a pressure of the supplied multi-component fluid mixture (41) and / or the solvent (42) is changed stepwise and / or continuously within a clock unit.

6. The method according to any one of the preceding claims, characterized in that a temperature of the supplied multi-component fluid mixture (41) and / or the solvent (42) is changed stepwise and / or continuously within a clock unit.

7. The method according to any one of the preceding claims, characterized in that the composition of the solvent and the content of at least one modifier in the multi-component fluid mixture is changed stepwise and / or continuously.

8. The method according to any one of the preceding claims, characterized in that at least one solid is used, which is adapted to cause different migration speeds of the individual components of the multi-component fluid mixture in the individual chambers or chamber sections.

9. The method according to claim 8, characterized in that the solid is an adsorbent material.

10. The method according to any one of the preceding claims, characterized in that as solvent (42) a mixture of a plurality of fluids and / or a mixture of at least one fluid having at least one low or high molecular weight

Modifier is used.

11. The method according to any one of the preceding claims, characterized in that as solvent (42) and / or multi-component fluid mixture, a gas or a mixture of a plurality of gases is used, which / is in the supercritical or subcritical state.

12. The method according to any one of the preceding claims, characterized in that the solvent (42) contains components to be separated.

13. The method according to claim 12, characterized in that the solvent with the components to be separated and the solvent without the components to be separated have different composition and / or capabilities with regard to influencing a bonding behavior of the components to be separated from the solid.

14. The method according to any one of the preceding claims, characterized in that in the chambers (49 - 52) or chamber sections, a chemical reaction to

Production and separation of the components is performed.

15. The method according to any one of the preceding claims, characterized in that the connection points of the first and second inputs and outputs (45 - 48) are repositioned at different times.

16. The method according to any one of the preceding claims, characterized in that at least one volume flow of the multi-component fluid mixture (41), the solvent (42), the extract stream (44), the raffinate stream (43) and circulating internal circulation streams within a clock unit stepwise and / or continuously is changed.

17. The method according to any one of the preceding claims, characterized in that the circuit is an open circuit.

18. Apparatus for carrying out the method according to one of the preceding claims.